The present invention relates to a fastener for enclosing and holding the outer circumferential surface of an elongated member such as a wire harness, and capable of being used for attaching such a member to a support.
Fasteners comprising a base unit for making contact with and holding the outer circumferential surface of elongated members such as wire harnesses or pipe, and an arm, hinged to the base unit, having an engagement part for engaging a corresponding engagement part in the base unit provided at the free end, and curved so as to form a loop in cooperation with the base unit when engaged to the base unit engagement part, are known. See, for example, Laid-Open Utility Model Application No. H7-34283/1995, gazette publication (Patent Literature 1). This fastener comprises: a base unit for holding a portion of the outer circumferential surface of the member; an arm, a first end of which is hinged to a first end of the base unit, curved so as to form, in cooperation with the base unit, a loop for holding the member; a base unit-side engagement part deployed at a second end of the base unit; and an arm-side engagement part, deployed at a second end of the arm, for engaging the base unit-side engagement part so as to form the base unit and the arm into the loop. A first pressing piece is hinged to the first end of the arm so as to extend toward the second end of the arm, and a second pressing piece is hinged to the second end of the base unit so as to extend from the base unit. The tip of the second pressing piece enters in between the arm and the first pressing piece when the base unit-side engagement part has engaged the arm-side engagement part. The first pressing piece and the second pressing piece cooperate to fill in the gap between the member and the arm.
Accordingly, advantages are realized in that, even if the member, such as a wire harness, is small in diameter, the superimposed thickness of the two pressing pieces increases to fill in the gap between the arm and the member, so that the member can be firmly held, and the insertion length (stroke) required to insert the arm-side engagement part into the base unit-side engagement part can be minimal, as with a large-diameter member, and the length of the arm-side engagement part can be short.
In addition to the fastener described above, fasteners which can hold wire harnesses of different outer diameters, are disclosed in Laid-Open Utility Model Application No. S62-25307/1987, gazette publication (Patent Literature 2) and the No. 1 gazette publication similar to Design Registration No. 942517 (Patent Literature 3). In the fasteners in Patent Literature 2 and 3, no innovative mechanism is provided for filling in the gap between the arm and the member when a member such as a wire harness is of small diameter, so that the advantages seen in Patent Literature 1 are not obtained. Laid-Open Utility Model Application No. H7-4977/1995, gazette publication (Patent Literature 4) discloses a clip which can attach an elongated member such as a wire harness to a headed stud or so-called T stud. This clip has a long band and a band fastener for holding an elongated member, and is configured such that the outer circumferential surface of the member is enclosed with the band, which is passed through the band fastener and tightened down to hold the member. This clip, while avoiding a gap between the band and the member, requires a long band, and the advantages seen in Patent Literature 1 are not obtained.
As stated in the foregoing, the fastener in Patent Literature 1 is preferable to the fasteners or clip in Patent Literature 2 to 4 because it provides advantages, namely, that it can firmly hold a member such as a wire harness, that the insertion length required to insert the arm-side engagement part into the base unit-side engagement part can be minimal as with a large-diameter member, and that the length of the arm-side engagement part can be short. Nevertheless, even with the fastener of Patent Literature 1, when a force is applied tending to move the fastener in the axial direction relative to the elongated member, the first pressing piece that is directly pressing against the member will be dragged by that force, and there is a danger that the hinge part connected to the arm will break, and, if it breaks, there is a danger of the holding force declining.